In recent years the development of caps for closing containers has proceeded rapidly in two different areas and objectives. Usually, these objectives are mutually exclusive. First, many caps have been suggested which are denominated as "childproof" or, more properly, "child-resistant" and many of such caps have been extremely complicated to close or to open, expensive to manufacture because they consist of more than one unitary part and unsatisfactory in use because many of them are so resistant to opening that it is difficult even for an older child or an adult to open them. Some have been so designed that replacement is also difficult. Secondly, many caps have been designed which are denominated "tamper-proof", the objective being to provide a cap for the container which will immediately indicate whether or not the container previously has been opened. Many of these caps also are expensive, difficult to open initially and, in many instances, impossible to restore for recapping the container.
Problems of this type have been particularly acute in wide mouth containers such as those in which relatively large quantities of foods are supplied to institutions or to commercial establishments. In such places, the content of the container frequently is not emptied at once but partially emptied from time to time over a several day period so that it is necessary that the container can be reclosed after having been opened. It is also important that, if possible, it be immediately apparent to someone examining the container whether or not it previously has been opened.
To a considerable extent, the attempts to devise tamperproof closures for containers also have resulted from the fact that in large supermarkets the activities of the shoppers cannot be supervised and some persons have the habit of removing the lid or cap from a container of an expensive product and substituting for it a cap of a less expensive product so that when the expensive product goes to the check-out counter, the clerk charges the customer for the less expensive product but the customer obtains the more expensive product. If a tamper-proof cap is placed upon such a product, the clerk can quite readily perceive that the cap has been removed and that the customer is attempting a fraud.
While most child-resistant closures have been designed for the purpose of closing containers of dangerous substances, it also would be desirable if containers of nonharmful products were provided with child-resistant closures. Even such a simple product as dill pickles or catsup could become harmful to a small child if that child were able to open the container and consume, say, a quart or a gallon. At least, in many cases, a small child opening such a container will spill the contents on itself or on its surroundings and the prevention of this type of activity also is desirable.
It is, therefore, the principal object of the instant invention to provide a tamper-indicating closure combination wherein the cap and the neck of the container have cooperating means by which the cap is permanently positioned on the container in closed position and cannot be removed without actuating a member which immediately reveals that the cap has been removed. In addition, a cap embodying the invention readily can be initially placed on a container having a proper neck configuration at a factory which fills the container and readily can be restored to closed position on the container by an older child or adult who has opened the container.
It is yet another object of the instant invention to provide a closure combination comprising a unitary cap and a cooperating neck finish on a container which initially is tamperproof and which continues to be child-resistant no matter how many times it has been opened and reclosed.
Yet another object of the instant invention is to provide a child-resistant closure comprising a unitary cap and a cooperating neck finish on the container which automatically compensates for compression of the cap liner which may occur after the cap has been removed and replaced a number of times.